SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac1d3d7b64a1bcdfc770e176b67cd32d30bbb7f5a7b4734010b54f09065768d8' 
  AND token = 'A5QsfOENnR/lIi54bo10O1HBiTRvWKpHmIkPF1/Mqf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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