SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0d7f5e4a8324fba23b443212c1de1026c161c8658cd0d171d34c05763388b17' 
  AND token = '7pyRsaFlG6i2q4Y8ly57d9fX8I7RRrPRuTvf7ktONLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}