SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ed5686de1abacfea389681c8f8f7efc139adeb1d624ea6e0b2db3a67ba51d1' 
  AND token = 'WhcDwJIlaVpJrmTSc5sFtba+713W1f4kDf5QKdJSk/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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