SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc8ff068068ee27ed87926cff0aa334100b5e9c373dc1c5c18e7dc902afa8820' 
  AND token = 'dCgDoFbk+MNCLyPQjpGhhLJoe40df6Ha+oIEL+ZP10U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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