SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a6a340b0b2cffa37cf8523268ef6f53324f52d561412f7064e185e44370918b' 
  AND token = '5YSP1KoCmL3dCqN/gGRGlxZt5zN/rTnvV0ceQYDmczo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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