SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bc8b298ff7684b2dc85b9874cf845ffaa325721a4390e05cfeb208eeee008b8' 
  AND token = 'jb65tGOAUiaQNxO5g29Zf/8yjOCNf18SiMfehsjLSIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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