SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd8cc718bf48cb70da40ce9b750dc4b76b44f0b52591dededdc5d29eac58b92' 
  AND token = 'R29s42xEhPX0aro3lLp0iPeLARlKtVW3WUbL7U/g/2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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