SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42d35e5011016a9860ef01e28d6bb61fdecf7d98e771fbb0befef4b6bcd8362d' 
  AND token = 'CO3Ir/0wvh5n5KYZDpRdwI9bzKIm2TVgSY/6gwX3NvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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