SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa345585786426b2ba7a1e2d9411e983c9a1564a3b1ae045e6cf022436f3dbc3' 
  AND token = 'TjGyMNZqEZNWAfhKobUj79Zz84Hk/uYs0/LOQ2Sbn1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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