SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c91fe4c435c3a9d513949bf42b13f75a39c12948477974152b835890ec1e4478' 
  AND token = 'M0wEepcmPRtI64zOqpKv6jKuqsUwf5ITN9hoE8P5GEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}