SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f687edc26f65e1332c1e160288e799d9ad6f5dd313f6282c585f0c430763e2b8' 
  AND token = 'unJCG4jepJ+uyvwGEme1r+bOBwxrIM17gDz+Z6C/H30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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