SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c98bc9d2a5770b4d2a9954d744aef170899b2b8583af3a27d2822a16cd7658af' 
  AND token = 'GTKBLSkhP+EjoWD1EZqq9vUwYP7foWFQlIqk3YE8Fmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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