SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b15b0d560381c4a83414cd68b4a64d924909b33537ad7d544449ce34bef3493a' 
  AND token = '7W2G4jOpmRyd2oPQz2LQbL1eLY0PXeftKkRUU03p6PA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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