SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '66a51f1f0da48fe5cfac681cb79fec03c9f56208bde9cfd4d03111c759890940' 
  AND token = '7P3Mevbwnzp4Ler/zAIR0BANva4eXJNu6z4LONllQ50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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