SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c4d0322c9f7e922bb2b5553090383fe7165dfa3784ea35c883a504fbb6948ef' 
  AND token = '77ha6ye2UIXsXb0619fVKxAg+RjHT3tIUNpsrPtViZo=' 
  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"
    }
  }
}