SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f215c0a511977c4e58b0c3927eef468df424878f49e1f1e349e63f82ee8be529' 
  AND token = 'VVIsN7urshNLHFmtYJ18RNRGCVySJ+4+jIqL/VPj6EY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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