SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4b17e1acbf464c463c9c78c4a000dd599972d08b00146ecb03aaa194d2f3de5' 
  AND token = 'vgepvPK/v/qHRhoEADxdP+YN0Gll+pW2pzip2sYwflE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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