SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96a3fe0bbaebc0db40991f5edd0d7d4f480e45dc265ca138dae0473a128fd966' 
  AND token = 'U3jLrhqkarioW2IzKiWVonC7MwKMOCqSAKn2s4RbtvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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