SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b437cec528a9bb582e1ea9aabb059a1d884c631913053be126804583c2da64a2' 
  AND token = 'lWTNOp6yO79LDEqiFvlBRYNLhNUSSg64e2tuaiPtmbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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