SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a60ec8a1942790118b3cee1aa9d62e5a1c83216e69dfc6288c72df23f1e267d' 
  AND token = 'fQn6ifXAeVAk/eqIAuAiYXSBgz2YcJQARMIQSFY5bns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}