SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79e362760e0f0f7b0a48c8bb5af2b29e55bbf0b49794a4ffd791f1d668c9f73b' 
  AND token = 'iNZ3ycBH+VNGLaRbjlOF5GzwIhbQfaUA/3sVOwhLCV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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