SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10e29f166e60050ee41bfb7a510c785e254b41c783672027991395efac845dd7' 
  AND token = 'DfG6wJxpRmfD/C3DGQYE9JfBBL3VCSUrsrxP6D6bzAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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