SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae009b32a375aeaf9d26d253cf4e50805d7d8986a9a4639dd459f05c9fc52282' 
  AND token = 'sgDS6aQod/3aKubfhFzgdL3QM6AOh+n3Zfgd1vyKk74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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