SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9313e98d2cead84302ac13e29981a1f1f0685ee8efccc019afbfb37955cd8ed' 
  AND token = 'dQ7nlPS02bL03owG80hQyFOfMszWGHCDZWUQ/oqIXk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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