SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18b5deb4720d8545fc2927a13ccdf632e064e86c417a7738b3b0fb73067220d6' 
  AND token = 'TiR81VefqPtMdcnAL/YKwpyptINBtiTpnqUPDQkqIhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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