SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b3e702acb6e819b4bf4fac40a0298ce6ecd68d000599c307d6ef809df078b9' 
  AND token = 'xk+bcrY6mohmJepACoIntTfdKSPBJMt6CTLZmMz03QE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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