SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a4d199336083b6dbb60df5e474466099bd47d1452792f0d9056626d0e6ba278' 
  AND token = 'Otp5kCvGfuL/CbBrhfW91Rp8DVGAMW71m6UQqE4hBds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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