SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d97717424a141913fb97865b107ece161d076e45890206018ed1785263f4c08' 
  AND token = 'UxRHkFReyd+ghAIjTBbBB3Za4dWdqhJ375JpsD63CN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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