SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf25def38e67604d1b1d69d8f7313418c4a39daffa187773f4f8e9dbab52e96b' 
  AND token = 'h/Nx+YzAL/zRWjm2sZgp3BHChdOH89LEyZ3H5J5uCdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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