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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e798b19575e24358bcc4b7fc054eb94da89175d98eb4e7d3e88ca74efae582ed' 
  AND token = 'fMQCvrdkAjBgeGpb/Zt0qSjlmmi+Zxhuq9wP0H1tvRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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