SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '712fd891d548af6b81c9f8b923e72002778cd82a5ff420ca0fae9ee275567cd0' 
  AND token = 'NxVMgZTOBWnM5GMcFNec/dy8UmuEQ5+Jd9rYmXXYtE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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