SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f99d01c862fa2b904dae1556b55712b9dfa96fe3e292998a00efdfce0e06494e' 
  AND token = 'Bdqt837cj+JawWiYmhdl9ZjAquB1jaijc2zdPda7sbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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