SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '189015ff94b807c47a455c5f40246872d44f50651b387daf570d18c65c85fad7' 
  AND token = 'saHjlIbS7NXpo6iHWgqaNZvMKJDM3/oafKmTAOVAqSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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