SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c77d1d746b3f27a681a2c4f38e05adcdc8acb28a52dd192a16d856a6abc8fac' 
  AND token = 'k9fZ9M3ZzpABX93kwJdzC+zGrjvq2qG2Lg84IeJPFqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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