SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b52e9b00632f9822cb63d2e0b19d27bb7d57e74c3288cd6ab74af2e28ff3a493' 
  AND token = '/m2LgKvG6aHWkjaH+1cAKQglXioyA55J7B8M3UC/Igk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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