SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd21221e99f2758173301ed66b8b491157155781d71c3905bb25e943d7dbf206' 
  AND token = 'Wuz52Q3Roi5JbooYa1xv2q7DUWOJAMKxX99/vLBkChc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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