SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afa0a62b313429a58acd758b06573c19195403ed3e8b150854b94ba19d363fe8' 
  AND token = 'BFrFEe7gDfIxkIMSaKbUaPpL/8X3KYn4SetORXSbDC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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