SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53e85ab593d5ce510374fa352588e73675653d7e370a25b80a8b644030644f1a' 
  AND token = 'iCEVtrQFVcqwFZTIIABSrM9xLTycCCkV6ESZlDpPc/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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