SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29da3d196c276b00ae62e745b594ad5593829c5bcd7e1c1a7bcc0f7afda73881' 
  AND token = 'oxmDBN3P2wqYdjyHjGMuMWILaiLD0gqx1gXDkU8Mey4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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