SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce6910cc51ecc3afddb9b3b08ef48140cea589ce85d8b5397b195ea9dc70921c' 
  AND token = 'rhhL0auNR16tN6fv2Soc2oj0bWp+ik4xKQa9ciiXurs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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