SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7fecf63fc0cb6cb551198c1ff4d45c47cecad96fa78523d10250eefba3e96c2' 
  AND token = 'zHxWLUmweBUcL9jJIJXZ0Y/zfAf+icrkUu3nL9M+yPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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