SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf0bcb34f1183392603d32b8784a97bb4bab26fc1f3e1ef3a798ec624f14b1e6' 
  AND token = '2Myy8BPe30Rl2fmlKEtFkBZ0QXUHc3eMf2juBw2PfuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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